Anesthesiology
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Carbon monoxide forms via reaction of isoflurane, enflurane, and desflurane with dried CO2 absorbents. The authors hypothesize that interventions by nonphysician support personnel to decrease absorbent drying will decrease the exposure rate of patients to carbon monoxide from anesthetic breakdown. ⋯ These interventions reduced patient exposure to carbon monoxide. Monitoring for carbon monoxide exposures during general anesthesia may be necessary to recognize and end patient exposures that occur despite preventative measures.
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Randomized Controlled Trial Clinical Trial
Dose comparison of remifentanil and alfentanil for loss of consciousness.
This study evaluated the efficacy and safety of remifentanil, a potent mu agonist opioid with a rapid onset and offset of effect, as a sole induction agent for loss of consciousness (LOC) and compared it with alfentanil. ⋯ Remifentanil is 15 times more potent than alfentanil, based on the ED50 to achieve loss of response to a verbal command and 20 times more potent than alfentanil based on the EC50. Neither opioid is suitable as a sole induction agent.
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Randomized Controlled Trial Clinical Trial
Dose-range effects of clonidine added to lidocaine for brachial plexus block.
Although addition of clonidine to local anesthetics can prolong pain relief after peripheral nerve block, a dose-range effect has not been determined. ⋯ This study suggests that a small dose of clonidine enhances the quality of the peripheral blocks from lidocaine and limits the classical alpha2-agonist side effects to sedation.
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Randomized Controlled Trial Clinical Trial
Oral clonidine premedication does not alter the efficacy of simulated intravenous test dose containing low dose epinephrine in awake volunteers.
Clonidine premedication modifies the hemodynamic responses to sympathomimetics. The present study was designed to test whether clonidine altered the response to a small intravenous dose of epinephrine, such as that which might be used in an epidural test dose. ⋯ Oral clonidine does not alter the efficacy of epinephrine-containing test doses used for detecting intravascular injection.
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Increased carboxyhemoglobin concentrations in patients receiving inhalation anesthetics (desflurane, enflurane, and isoflurane) have been reported. Recent in vitro studies suggest that dry carbon dioxide absorbents may allow the production of carbon monoxide. ⋯ An oxygen flow rate of 10 l/min for 24 h in a conventional anesthesia circuit can dry carbon dioxide absorbents sufficiently to produce extremely high levels of carbon monoxide with high carboxyhemoglobin concentrations in desflurane-anesthetized pigs. When the reservoir bag is in place on the anesthesia machine or when a lower oxygen flow rate (5 l/min) is used, carbon dioxide absorbent drying still occurs, but 24-48-h exposure time is insufficient to allow for carbon monoxide production with desflurane.